I don't know, how much it is true, but I read somewhere, that Russia operate only around 300 Mi-24 and they are planing to buy 300 Mi-28N, 140 Ka-52 and 50 Mi-35M, so more than one for one...
Perhaps that answers our questions about how the Mi-28 is entering service without the fully President-M system fully integrated or why they are buying Mi-35M2 and Mi-28N and Ka-52. Last time I read about numbers there were over 500 Hinds in service so various conflicts and exercises have clearly taken their toll on numbers, plus of course many were simply due for retirement anyway... helicopters are fairly high maintainence vehicles so it is no surprise that after 20 odd years of neglect that they might be in bad shape and need replacement.
True. I also think that every S-400 battalion get one battery of Pantsirs for protection. This year RuAF will have 8 battalions of S-400 and let say 20 previous and 28 from this year, they will have 8 batteries of Pantsirs to complete their protection.
Their versatility and mobility also make them very useful... I would expect they will try to get as many as they can afford.
In terms of performance at sea nothing shows the improvement more than a small patrol boat getting Pantsir-S1 to replace a Kashtan-M mount. Now Kashtan-M is a good system with its 10km range missiles and 4km range 30mm guns the biggest threat to a small patrol boat... helicopters and fixed wing aircraft are kept at arms length with very few helos able to attack with common weapons from more than 8km or so.
Compared with a MANPADS turret firing mistral or stinger or igla which max out at 6-7km a helo like an Apache can stand off with 8km range Hellfires and hammer that boat. The boat will not be fast enough to outrun or out manouver a helo and would rely on trying to shoot down the incoming missiles.
With Pantsir-S1 the range of the missiles extends the engagement range to 20km which means that helicopters can be engaged before they launch.
The flat open sea is one thing however, on land the advantage shifts even further in favour of the ground platform because the radar picture of the surrounding airspace can be accessed via datalink with the ground vehicle able to search passively using thermal and optical sights and the terrain can make detection of the ground vehicle difficult or impossible till it is too late. The clever use of terrain to defend a target means you can place individual vehicles in places to passively detect threats and pass target data on to the rest of the defence... for instance imagine a flat open valley with something you are protecting on that plain, but there is a small hill 4-5km away that an enemy might use to observe from behind. Your vehicles around the target can't see through the hill so an approach from behind the hill and then popping up from behind the hill to observe and then launch an attack from makes a lot of sense... except the defenders already thought of that and have stationed a 2-3 Pantsir-S1s in the forest beyond the small hill which the attacking helos flew over on their way to the small hill. Those vehicles would pass target data to the IAD network and a squad of fighters is on the way... after they launch their attack (they can do so from medium range because the targets have already be identified as hostile and are cleared to fire) any survivors can be mopped up with the forward located Pantsir-S1s which can each engage 4 targets at a time... though I would think of a flight of 6-8 helos that the fighters will have taken out more than half with R-77s already... of course an observation unit on top of the small hill with Iglas could also have called up an air attack and alerted the ground forces, but if instead of half a dozen helos the threat was 20-30 cruise missiles flying low and fast with the first missile aimed at the radar station on top of the hill then lets assume the first warning is the first cruise missile detected at 10km by the radar on top of the hill, decoys and jammers would be pointless as the missiles are guided to a coordinate rather than a signal, but the very high speed of the Pantsir-S1 missiles might make interception possible if they are ready. Border assets detecting the incoming missiles several minutes before hand would greatly increase the chances of survival. If alerted the three Pantsir-S1 vehicles could take on 12 targets at once till they run out of ammo. The radar on the hill could possibly survive because only the first few missiles will be going for the radar, the rest will be aimed at the known AD vehicle positions around the target and the target itself. Early detection would also lead to getting fighters into the air and their efforts will thin out the numbers of threats the ground based systems will have to deal with...